When is a child too sick to go to school?

PHILADELPHIA -- When Marge O'Farrill's son Christopher complained one recent morning that he was feeling lousy, with a stuffy head and sore throat, she had a decision to make.

School nurses offer these general guidelines for keeping sick children out of class. After each sickness is the guideline for returning to school. If in doubt, consult your pediatrician.

Chicken pox -- When old blisters have formed scabs, and there are no new ones.

Conjunctivitis (pinkeye) -- When eyes are clear or have been treated with antibiotics for 24 hours.

Any undiagnosed rash or fever -- When symptoms are gone for 24 hours.

Vomiting or diarrhea -- When symptoms are gone.

Scabies (body lice) -- 24 hours after start of treatment.

Strep throat or scarlet fever -- 24 hours after start of treatment.

Impetigo -- When skin is clear or child has been under treatment for 24 hours.

Head lice -- When head is treated and free of lice and nits.

Should she keep him home or send him to school?

O'Farrill thought her 13-year-old son would feel better once he was up and moving, so she told him to take a hot shower to clear his head, then gave him a decongestant and a big glass of orange juice. Go to school, she suggested. ''See how you feel.''

But not long after the Newtown Square mother bid her son goodbye, she got a call from the nurse at Paxon Hollow Middle School. Christopher was feeling miserable. Could she come and get him? He ended up missing three days of school.

With cold and flu season bearing down, many parents are facing similar early-morning predicaments.

Sometimes, the call on whether to keep a child home is clear: He has been vomiting all night and is still feeling queasy. Or she looks flushed and has a high fever. School nurses have a list of ailments for which children shouldn't be in school, including an undiagnosed fever or rash, chicken pox, conjunctivitis (pinkeye), head lice, and strep throat not yet being treated with an antibiotic.

But often the symptoms aren't so dramatic -- a runny nose, coughing, a general malaise described as ''I don't feel good, Mom.''

For parents hurrying to get the kids to the bus, the decision to send or not to send isn't always easy. And when both parents work, there's an added consideration: Who's going to stay home?

School nurses say they are seeing more kids than they used to with ailments such as diarrhea, serious colds and fevers.

''Schools are really a reflection of society. As you have more parents working, you have more kids coming to school sick,'' said Marti Engle, a nurse at Devon and Beaumont elementary schools in the Tredyffrin/Easttown district, Chester County, Pa.

Pat DiNenno, school nurse at Paul V. Fly Elementary School in Norristown, Pa., thinks that more children are fending for themselves in the morning -- with no adult to assess whether they should stay home.

It's not unusual for 35 or more of the school's 550 students to come to her in a single day with stomachaches, sore throats and other problems. On a recent Monday, it wasn't even 9 a.m., and she had six children in her office saying their stomachs hurt.

Still, DiNenno isn't quick to send kids home. She carefully reviews their symptoms and then checks their temperature with an oral thermometer.

Unless it is 100 or more, or the child has vomiting or diarrhea, she usually sends them back to class. Often, a stomachache is nothing more than an empty stomach because the child skipped breakfast, and a snack solves that.

''I tell them, your job is to be in school,'' she says. ''Some days, you're not going to feel that well.''

When a fourth-grader came to the nurse's office mid-morning saying her throat hurt, DiNenno took her temperature, used a tongue depressor to look at her throat, and gave her warm saltwater to gargle.

''I know you're going to feel better as the day goes on,'' DiNenno reassured her as she sent her back to class.

Parents have their own ways of sorting out complaints.

Shirley Gay, mother of Emily, 14, and Andrew, 11, says she simply does what mothers everywhere do: She feels the forehead to see if it's hot.

''I never understood that until I was a mother,'' she says. A fever is a reason to stay home, but on questionable cases, ''I do what my mother did. I say, 'Well, you know what you're missing at school. ... Think about it, and you know you're going to have to make it up.' ''

Two weeks ago, she kept Emily at home in Media, Pa., after she complained of dizziness, headache, sore throat and stomachache. It turned out she had a sinus infection.

School nurses say it's not unusual for a child to feel perfectly fine heading off to school, only to crash a short time later.

Faced with a feverish child, some parents will give a dose of Tylenol and then send him off to school. Nurses say that's not a good idea, because the fever will return once the medicine wears off. And fever is the sign of an active infection -- one that could be passed on to someone else.